Why hoppers bad

hoppers cause severe lag in large numbers, like everything else in minecraft

try it, worldedit a 100x100 area top to bottom full of any block that has some functionality (noteblocks, furnaces, enchanting tables, hoppers) and see how the server holds up when those chunks are loaded

 

if you remove the ability to craft them then there are less on the server

 

or none...

 

The way hoppers move items isn't overly brilliant. It can cause huge lag because of it.

 

u could sell em in shops for high price